madstaff, I didn't mention the TCR as I got the impression you were looking for a manual gearbox car. 7,5 DSG is 7 speed (PP&TCR) over 6 speed in mk7, so that would be another positive for 7.5 if you were that way inclined?
Again, not all mk7 CS are equal at 4 years old. I tend to buy my cars privately, you can get an idea of how it is used.
Mine went through 10k miles yesterday, is fully serviced with ceramic coatregularly topped up, it appears to be in better condition than a neighbours 18 plate Golf R, so he say's anyway!
The buckets are fine for daily use, the only real issue is if you have a rear passenger, you need to tilt the back rest forward, but manually move the seat forward from the lever on the front of the seat. This can't really be done by a rear passenger on their own?
The standard seats are good, same as the regular Gti with different trim, however, at this time a regular GTi had heated sets as standard, not so in the CS. It was an option, but winter pack with heated seats is really rare on a CS with the standard seats.
18"s ride well and look good, from experience DCC is worth having with 19" wheels (as per CSS).
See, how buying the right car can be a literal needle in a haystack?

Buy the best you can afford and available at the time.